Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Non-genetic processes in development and heredity
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.ORCID iD: 0000-0002-9517-485x
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There is a swiftly increasing amount of empirical evidence that non-genetic factors, such as DNA methylation and small RNAs, play an important role not only in development but also in heredity and, therefore, evolutionary dynamics. One of the most interesting aspects of non-genetic processes is their responsiveness to environmental conditions, which has been shown to affect not only the phenotype and fitness of the individuals directly exposed to the stimulus, but also their offspring even when the stimulus is no longer present, indicating that the transmission of non-genetic factors across generations might work analogously to immunization against recurring conditions. In this thesis, I explored the effects and consequences of non-genetic processes in development and heredity, from both theoretical and experimental perspectives. In Article I, I created a mathematical model of DNA methylation dynamics during the maternal-to-zygotic transition, leading to the zygotic genome activation. I found that there is a developmental constraint on the transition between different cell lineages, with an increasing flexibility of active methylation and decreasing flexibility of maintenance (de-)methylation. In Article II, we explored the dynamics of small RNA production throughout development, including their amplification, transgenerational transmission and responsiveness to environmental conditions. Responsiveness of small RNA production resulted in greater benefits when soma and germline are both responsive, especially in highly correlated environmental conditions. In Article III, I carried out experiments on zebrafish to explore the effects of the male social environment on sperm production in terms of sperm morphology and DNA quality. Males exposed to different social treatments produced sperm with different morphologies and DNA integrity levels. In Article IV, we used the same experimental design to look at the effects of the male social environment on offspring development in terms of differential gene expression patterns. Males exposed to different social treatments sired offspring that showed different expression patterns of genes involved in post-transcriptional processes of gene expression regulation.  Our findings shed light on the importance of non-genetic processes in development and heredity and contributes to the current knowledge about which and how non-genetic mechanisms can potentially affect evolutionary dynamics.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. , p. 44
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1718
National Category
Evolutionary Biology Genetics Developmental Biology
Research subject
Biology with specialization in Evolutionary Genetics
Identifiers
URN: urn:nbn:se:uu:diva-359653ISBN: 978-91-513-0435-9 (print)OAI: oai:DiVA.org:uu-359653DiVA, id: diva2:1245599
Public defence
2018-11-07, Lindahlsalen, Norbyvägen 18A, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2018-10-10 Created: 2018-09-05 Last updated: 2018-10-16
List of papers
1. Methylation dynamics during the maternal-to-zygotic genome transition in dioecious species
Open this publication in new window or tab >>Methylation dynamics during the maternal-to-zygotic genome transition in dioecious species
2018 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 13, no 7, article id e0200028Article in journal (Refereed) Published
Abstract [en]

The starting point of a new generation in sexually reproducing species is fertilization. In many species, fertilization is followed by cell divisions controlled primarily by maternal transcripts, with little to no zygotic transcription. The activation of the zygotic genome (ZGA) is part of a process called maternal-to-zygotic transition (MZT), during which transcripts from the zygotic genome take control of development, setting the conditions for cellular specialization. While we know that epigenetic processes (e.g. methylation) are involved in the MZT, their roles and interplay in the transition are largely unknown. I developed a model and used simulations to elucidate the interaction between possible epigenetic processes, namely methylation processes, involved in the MZT. The model focuses on the dynamics of global methylation levels and how these interact with factors such as a parental repressor and the nucleocytoplasmic ratio to trigger the ZGA, followed by development from fertilization to adulthood. In addition, I included transgenerational effects transmitted to the zygote from both parents through their gametes to show that these may set the stage for plastic developmental processes. I demonstrate that the rates of maintenance methylation and demethylation, which are important for the achievement of the final methylation levels of an individual, exhibit a certain level of flexibility in terms of parameter values. I find that high final methylation levels require more restricted combinations of parameter values. The model is discussed in the context of the current empirical knowledge and provide suggestions for directions of future empirical and theoretical studies.

National Category
Genetics
Research subject
Biology with specialization in Evolutionary Genetics
Identifiers
urn:nbn:se:uu:diva-356599 (URN)10.1371/journal.pone.0200028 (DOI)000438170300026 ()29990374 (PubMedID)
Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2021-06-14Bibliographically approved
2. Evolution of small RNA production under fluctuating environmental conditions
Open this publication in new window or tab >>Evolution of small RNA production under fluctuating environmental conditions
(English)Manuscript (preprint) (Other academic)
National Category
Evolutionary Biology Genetics Developmental Biology Ecology
Identifiers
urn:nbn:se:uu:diva-359418 (URN)
Available from: 2018-09-01 Created: 2018-09-01 Last updated: 2018-09-05
3. The effects of male social environment on sperm phenotype and genome integrity
Open this publication in new window or tab >>The effects of male social environment on sperm phenotype and genome integrity
Show others...
2019 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 32, no 6, p. 535-544Article in journal (Refereed) Published
Abstract [en]

Sperm function and quality are primary determinants of male reproductive performance and hence fitness. The presence of rival males has been shown to affect ejaculate and sperm traits in a wide range of taxa. However, male physiological conditions may not only affect sperm phenotypic traits but also their genetic and epigenetic signatures, affecting the fitness of the resulting offspring. We investigated the effects of male-male competition on sperm quality using TUNEL assays and geometric morphometrics in the zebrafish, Danio rerio. We found that the sperm produced by males exposed to high male-male competition had smaller heads but larger midpiece and flagellum than sperm produced by males under low competition. Head and flagella also appeared less sensitive to the osmotic stress induced by activation with water. In addition, more sperm showed signals of DNA damage in ejaculates of males under high competition. These findings suggest that the presence of a rival male may have positive effects on sperm phenotypic traits but negative effects on sperm DNA integrity. Overall, males facing the presence of rival males may produce faster swimming and more competitive sperm but this may come at a cost for the next generation.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
DNA damage, sexual selection, sperm competition, trade‐offs
National Category
Evolutionary Biology Zoology Genetics
Identifiers
urn:nbn:se:uu:diva-359415 (URN)10.1111/jeb.13435 (DOI)000472662300002 ()30817032 (PubMedID)
Funder
EU, European Research Council, HapSelA-336633Knut and Alice Wallenberg Foundation
Available from: 2018-09-01 Created: 2018-09-01 Last updated: 2019-08-13Bibliographically approved
4. Social environment of fathers affects gene expression patterns in early offspring
Open this publication in new window or tab >>Social environment of fathers affects gene expression patterns in early offspring
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Developmental Biology Genetics Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-359417 (URN)
Available from: 2018-09-01 Created: 2018-09-01 Last updated: 2018-09-05

Open Access in DiVA

fulltext(593 kB)434 downloads
File information
File name FULLTEXT01.pdfFile size 593 kBChecksum SHA-512
309760dca7b15e529a7db7ae8f3f3c83c62ac2bfa9ef91c6aea522b6ab34911d139277dd717b15f2719360bb7de2844ba9400acd89755b502be59a745329178c
Type fulltextMimetype application/pdf

Authority records

Silva, Willian T. A. F.

Search in DiVA

By author/editor
Silva, Willian T. A. F.
By organisation
Evolutionary Biology
Evolutionary BiologyGeneticsDevelopmental Biology

Search outside of DiVA

GoogleGoogle Scholar
Total: 434 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 701 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf